void OnWorkspaceRegionRegister(object sender, WorkspaceRegionEventArgs e)
{
e.Handled = true;
if (!regions.ContainsKey(e.Region.Id))
{
regions.Add(e.Region.Id, e.Region);
}
if (!workspaceChanging)
{
SyncWorkspaceRegionLayout(e.Region);
}
}
void OnWorkspaceRegionUnregister(object sender, WorkspaceRegionEventArgs e)
{
e.Handled = true;
regions.Remove(e.Region.Id);
}